code: def sdm_LC(f, K):
      """Returns the leading coefficient of ``f``."""
      if not f:
          return K.zero
      else:
          return f[0][1]
  
imports: from itertools import permutations
  from sympy.polys.monomials import monomial_mul, monomial_lcm, monomial_div, monomial_deg
  from sympy.polys.polytools import Poly
  from sympy.polys.polyutils import parallel_dict_from_expr
  from sympy.core.singleton import S
  from sympy.core.sympify import sympify
label_desc: Use image node_id 5 for calling a global function with example usage: sdm_LC(f, K) and returns: K, f